Catheter with enhanced pushability

Abstract

Apparatus for enhancing pushability and minimizing kinking of a balloon catheter is provided, wherein a catheter comprises inner and outer tubes, and a balloon that is proximally affixed to the outer tube and distally affixed to the inner tube. The catheter of the present invention further comprises a tubular member imposed on the inner tube which is configured to form a reversible mechanical linkage between inner tube and outer tube while an axially compressive load is applied to the catheter tip.

What is claimed is: 
     
       1. Apparatus suitable for enhancing pushability of a balloon catheter, the apparatus comprising:
 an outer tube having proximal and distal ends; an inner tube having proximal and distal ends and a guidewire lumen extending therethrough, the inner tube disposed coaxially within the outer tube to define an inner inflation lumen therebetween; 
 wherein a load-sharing member is imposed on the inner tube at a portion proximal of the distal end of the outer tube, and wherein the load-sharing member is configured to form a reversible mechanical linkage between inner tube and outer tube, while maintaining inner inflation lumen patency, while an axially compressive load is applied to a catheter tip; 
 wherein the apparatus further comprises a balloon having proximal and distal ends, wherein the proximal end of the balloon is affixed to the outer tube at a proximal affixation point and the distal end of the balloon is affixed to the inner tube at a distal affixation point to define a balloon segment extending therebetween; 
 wherein the load-sharing member has two fixation areas where the load-sharing member is fixed to the inner tube and a connecting body extending therebetween, and wherein the connecting body is configured to radially expand while an axially compressive load is applied to the catheter tip, thereby establishing the said reversible mechanical linkage; and 
 wherein the load-sharing member has a tubular form being a tubular member having an annular wall with a number of recesses extending through it; the number of recesses extending through the tubular member to maintain inner inflation lumen patency while the axially compressive load is applied to the catheter tip. 
 
     
     
       2. The apparatus of  claim 1  wherein shapes of the recesses through the annular wall of the tubular member are selected from a group consisting of a helical pattern, a lattice pattern, and a longitudinal parallel shaped pattern.